Code of Civil Procedure Article 148
After the requested authorities or public servants notify that service has been or cannot be effectuated, the court clerk shall include such notice in the dossier; in cases where service cannot be effectuated, the court clerk shall also notify the fact and the reason therefor to the party for whose purpose service was attempted.
中文原文 民事訴訟法第148條
受囑託之機關或公務員，經通知已為送達或不能為送達者，法院書記官應將通知書附卷；其不能為送達者，並應將其事由通知使為送達之當事人。